Using “bryophytes and their associated testate amoeba― microsystems as indicators of atmospheric pollution

Testate amoebae (TA) associated with terrestrial mosses are increasingly used in ecological and ecotoxicological studies. The TA community is sensitive to changes in its environment (climate change, metal or gas pollution). In this study, a “bryophyte-TA” microsystem was investigated as an indicator of dry particulate deposition and NO2 atmospheric concentration over an 8-month period in rural, urban and industrial sites in north-eastern France. The urban site was characterised by significant contamination with NO2, and the industrial site by significant contamination with Fe, Pb, Cr and Al. Different ecological descriptors of the TA community can be used as indicators of atmospheric pollution. Simple descriptors (total biomass or total abundance) are useful to indicate atmospheric particulate and gaseous pollution, while a complex descriptor (species richness) is useful to differentiate the source of pollution (urban or industrial) in winter and summer. Moreover, Redundancy Analysis showed that some species are negatively correlated with NO2 and particulate pollution. Principal Responses Curves revealed contrasting dynamics of the TA species biomass according to the type of pollution (urban or industrial). Our results bring further support to the use of bryophytes and associated TA as a biomonitoring tool for atmospheric pollution. Further studies are required to develop this tool and standardise it for potential general use.